Design of H-infinity-based Robust Controller for Single-phase Grid-feeding Voltage Source Inverters

TL;DR

This paper presents an H-infinity-based robust current controller for single-phase grid-feeding voltage source inverters with an LCL filter, achieving improved transient response, reference tracking, and disturbance rejection across varying grid conditions.

Contribution

It introduces a novel H-infinity control design tailored for single-phase inverters, addressing LCL resonance damping and implementation feasibility.

Findings

Fast transient response demonstrated in simulations

Superior steady-state disturbance rejection

Effective damping of LCL resonance

Abstract

This article proposes the design of H-infinity-based robust current controller for single-phase grid-feeding voltage source inverter with an LCL filter. The main objective of the proposed controller is to have good reference tracking, disturbance rejection and sufficient LCL resonance damping under a large range of variations of grid impedance. Based on the aforementioned performance requirements, frequency dependent weighting functions are designed. Subsequently, the sub-optimal control problem is formulated and solved to determine the stabilizing controller. Computational footprint of the controller is addressed for ease-of-implementability on low-cost controller boards. Finally controller hardware-in-the-loop simulations on OPAL-RT are performed in the validation stage to obtain performance guarantees of the controller. The proposed controller exhibits fast response during transients and superior reference tracking, disturbance rejection at steady-state when compared with proportional- and resonant-based current controllers.